3-aminomethyl cephalosporin compounds

ABSTRACT

A NEW CLASS OF METHABOLICALLY STABLE CEPHALOSPORIN COMPOUNDS IS DISCLOSED. THESE COMPOUNDS HAVE AN ALIPHATIC AMINOMETHYL GROUP IN THE 3-POSITION OF THE MOLECULE.

United States Patent Ice Patented 33323;

s-AMrNoMu r ri iziar ArosromN -iH-Co- J. Alan Webber and Earle M. van Heyningen, Indianapolrs, Ind., assignors to Eli Lilly and Company, Indianapohs, Ind. No Drawing. Continuation-impart of application Ser. No. Q

cm m-x(om .co-

703 523 Feb. 7 1968. This a lication F 26 serjNor 802,651 PP eh 1969 Int. Cl. C07 US. Cl. 260-243 c d 99/24 3 Claims 10 Q 1s hydrogen, hydroxy, chloro, bromo, C to C alkoxy,

n tro, or cyano; ABSTRACT OF THE DISCLOSURE Y silsltshylcllroglf, amino t artuli pharmaceutically acceptable er r A new class of metabolically stable cephalosporin comm i an integer 2f g f gammo pounds 1s d1sclosed. These compounds have an aliphatic i an integer of 1 to 2- amrnomethyl group 1n the 3-position of the molecule. X is oxygen or ulf r R is hydrogen or C to C alkyl and R is C to C alkyl I or R and R taken together with the nitrogen to which CROS'S'REFER'ENOE they are bonded complete a pyrrolidino, piperidino, or

morpholino ring; R; is absent or is hydrogen or C to C alkyl; Z is absent when R, is absent and is the anion of an acid having a pKa of less than 4 when R; is present; and

This application is a continuation-in-part of our copendmg application Ser. No. 703,523, filed Feb. 7, 1968, now abandoned.

BACKGRO D UND OF THE INVENTION R 1s hydrogen, a pharmaceuucally acceptable cation, C =Th1s invention relates to a new class of metabolically to C t-alkyl, C to C t-alkenyl, C to C t-alkynyl, stable cephalosporln compounds substituted in the 3-posibenzyl, methoxybenzyl, nitrobenzyl, benzhydryl, phthaltron with an allphatlc ammomethyl group. imidomethyl, succinimidomethyl, trimethylsilyl, or

fThe bcephalosporms constltute a well-recognized family phenacyl.

0 ant 'ot' l 1 and a liumber of representatlyes of thls fam When R in the above formula 1s hydrogen there 1s a 1 y are W1 e y used 1n the treatment of dlsease. The first f th 7 Wh n R h dro en members of this family were obtained from cephalosporin g g g gggfi fi ig g ii i g in i C, a f r t ti e men a on product or from Pemclum In accord 7-pos1t1on exists as a salt of the sulfonic acid. It will be ance with the process described in Morin and Jackson U.S P t. 3,275, a recogmzed that when both R and R are hydrogen a a 63 These early cephalosponns were sub zwitterion will exist. This zwitterion form of the comstituted in the 3- ositio w' group p D 1th a methyl or acetoxymethyl pounds is included as a part of thls inventlon.

It has long been recognized that improved antibiotics The more anliblotifiany i compounds of our mven' might be obtained by the introduction of other substituare those Whlch R1 18 the grmPs scribed above. Thus, for example, R may be such groups ents in the 3-position. Therefore considerable effort has 40 been devoted to the preparation of various 3-substituted as phenylglycyl methoxyphenylglycyl mtmphenylglycyl' cephalosporins 2 phenyl -2-hydroxyacetal, phenylacetyl, chlorophenylacetyl, phenoxyacetyl, cyanophenoxyacetyl, benzyloxy- SUMMARY OF THE INVENTION acetyl, and phenylpropionyl. When an amino group is present it may be protected by well-known groups such We have now obtained a new class of cephalosporln as t butyloxycarbonyl, benzyloxycarbonyl of 2,2,}

antibiotics wherein the substituent at the 3-position is an trichloroethox carbon 1 g g group 3 amglo i atom is The 3-amin methyl group of our compounds is one in su st1 ute W1 one or two 1 to 6 a y groups or is 1 a of a lli i ii iiiifinf iii zsrsih ziimrh :1: his Q 5 g i gi gi g i zfggifi g g g g af g fg a pyrrolidino, piperidino, or morpholino ring. Thus our compounds. These salts are2i those obtaingil by treating th g rllllg gs mzifiyl l gl igggidhgllii iltigyia-rpgrsfiglgflgithh $2 2: gi fii gg z g g i ig ng gg gg gigg aminomethyl, dimethylaminomethyl, diethylaminomethy], as a C to C alkyl halide /fi methyle'thylarninomethyl, dihexylaminomethyl, piperidino- 1 6 methyl, and pyrrolidinomethyl. In addition, salts, or

quaternary salts of these amino groups may be prepared DESCRIPTION OF THE PREFERRED by reaction with an acid having a pKa of less than 4 or a EMBODIMENT The novel 3-aminomethyl cephalosporin compounds of g g g gi i ggz ig jfigg g z g 3? our Invention are those represented by the formula chloric acid, methyl iodide, ethyl sulfate, or amyl nitrate. When such salts are prepared R would be respectively hydrogen, methyl, ethyl, or amyl while Z would be such R NH(lJH--CH 0H2 R2 groups as chloride, iodide, sulfate, or nitrate.

The most active compounds of our invention are those -CH N-R -Z O C 2 a in which R is hydrogen, 1.e., the carboxyhc aclds, or a pharmaceutically acceptable cationic salt of the aclds such COZRE as the sodium, potassium or ammonium salts. In the wherein; preparation of the acids it is frequently necessary to protect the carboxyl group by esterification. The esterifying R1 hyflmgfem hydrogen and a C6 to C12 hydrocarbon group is usually one that can be easily removed to resulfomc acld generate the acid. Typical of such groups are t-butyl, t-

3 amyl, t-hexyl, 1,1-dimethyl-2-propenyl, l,l-dimethyl-2- pentynyl, *benzyl, p-methoxybenzyl, p-nitrobenzyl, benzhydryl or phenacyl.

Typical examples of specific compounds of our invention are listed below:

3-dimethylaminomethyl-7-(ct-amino-u-phenyl) acetamido- A -cephern-4-carboxylic acid;

3-hexylaminomethyl-7- 2-phenyl-2-hydroxy acetamido- A -cephem-4-carboxylic acid;

t-butyl 3-dimethylaminomethyl-7- a-amino-a-phenyl) acetamido-A -cephem-4-carb0xylate;

p-nitrobenzyl 3-piperidinomethyl-7-phenoxyacetamido-A cephem-4-carboxylate;

3-diethylaminomethyl-7-amino-A -cephem-4-carboxylic acid bis-p-toluenesulfonate;

benzhydryl 3-diamylaminomethyl-7- (p-methoxyphenyl) acetamid-A -cephem-4-carboxylate; and

3-pyrrolidinomethyl-7-phenylacetamido-A -cephem-4- carboxylic acid hydrochloride.

The novel feature of our invention lies in the substituents in the 3-position. The R and R substituents may be any of those well known in the cephalosporin art. One skilled in the cephalosporin art can choose the proper R and R substituents to give the desired antibiotic activity with the particular aminomethyl group present in the 3- position.

Our compounds can be prepared from a penicillin starting material such as penicillin V by a multistep process beginning with the process described in Morin and Jackson US. Pat. 3,275,636 for the conversion of a penicillin sulfoxide ester to a desacetoxy cephalosporanic acid ester. The double bond in the 3-position of this desacetoxy cephalosporin ester is then isomerized to the 2-position and the 3-methyl group is brominated by treatment with N-bromosuccinimide. Treatment of the 3-brom0methyl compound with a primary or secondary amine results in the formation of the 3-aminomethyl derivative which can be separated from impurities by acid extraction. The double bond in the 2-position of the amino ester recovered from the acid extract can then be isomerized to the 3-position by either base isomerization or oxidation to the sulfoxide followed by the reduction of the sulfoxide to yield the A cephalosporin ester. The acyl group in the 7-posi-tion which was carried over from the penicillin starting material can be removed by reaction with phosphorus pentachloride in the presence of a tertiary amine followed by treatment with a lower alkanol, then with water or aqueous acid to form the 7-amino ester compound. The 7- amino group can be reacylated with the desired acyl group using procedures well known to those skilled in the art. The particular ester group employed can then be removed to yield the free acid.

The preparation of the compounds of our invention will be .further illustrated by the following examples.

EXAMPLE 1 A suspension of 0.353 g. of 3 methyl 7 phenoxyacetamido-A -cephem-4-carboxylic acid (prepared as described in US. Pat. 3,275,636) in ml. of benzene was cooled in an ice bath and stirred while 0.256 g. of oxalyl chloride and 1 drop of dimethylformamide were added. The reaction mixture was stirred at about 5 C. for minutes and the solvent removed under reduced pressure to yield the desired acid chloride of the starting A -cephem acid.

EXAMPLE 2 A solution of 1.75 g. of the acid chloride of Example 1 in 70 ml. of methylene chloride was added dropwise to a stirred solution of 0.72 g. of triethylamine and 4.0 g. of 3-methyl-1-buten 3 01 in ml. of methylene chloride maintained at ice temperature. Upon completion of the addition (about 90 minutes) the organic solution was washed successively with water and 3 percent hydrochloric acid and evaporated to dryness. The residue was dissolved in ethyl acetate, washed with 5 percent sodium bicarbonate solution, and treated with activated charcoal. The mixture was filtered and the solvent was removed from the filtrate under reduced pressure to give 0.51 g. of 2-(2-methyl-3-butenyl) 3-methyl-7-phenoxyacetamido- A -cephem-4-carboxylate. The structure was confirmed by the nuclear magnetic resonance spectrum. The neutral and basic washes yield 0.82 g. of a mixture of A and A acids.

EXAMPLE 3 A solution of 4.16 g. of the ester from Example 2 in one liter of carbon tetrachloride was stirred and purged with nitrogen for 20 minutes. To the solution were then added 2.67 g. of N-bromosuccinimide and 50 mg. of a20- bis-isobutyronitrile. The solution was stirred and heated under reflux until a negative starch-iodide paper test was obtained (approximately 4 /2 hours). The solution was cooled overnight in a refrigerator, the excess N-bromosuccinimide was removed by filtration through a cotton plug, and the carbon tetrachloride was evaporated to yield 2-(2-methyl-3-butenyl) 3 bromomethyl-7-phenoxyacetamido-A -cephem-4-carboxylate which was used in subsequent reactions.

EXAMPLE 4 A solution of 2.48 g. of 2-(2-methyl 3 butenyl) 3- bromomethyl-7-phenoxyacetamido-A -cephem 4 carboxylate, 2 ml. of morpholine, and 20 ml. of benzene was stirred at 25 C. for two hours. The solution was then washed with 5 percent sodium bicarbonate solution and the organic phase extracted three times with 3 percent hydrochloric acid. The acid solution was adjusted to pH 8 with 5 percent sodium bicarbonate and extracted with methylene chloride. The methylene chloride solution was dried over sodium sulfate and evaporated to dryness to give 0.74 g. of 2-(2-methyl 3 butenyl) 3-morpholinomethyl-7-phenoxyacetamido-A -cephem 4 carboxylate. A thin layer chromatogram showed this material to be nearly pure.

EXAMPLE 5 A solution of 0.7 g. of the product from Example 4 and 3 ml. of triethylamine in 20 ml. of a mixture of isopropyl and ethyl alcohols was stirred at 25 C. for 2 hours. The solvents were removed under reduced pressure and the residue examined by thin layer chromatography. This showed the presence of two components of similar R one of which corresponded to the starting material. The mixture was then stirred in percent formic acid for one hour after which time the formic acid was removed under reduced pressure. The residue was dissolved in water and the pH of the aqueous solution was adjusted serially to 8, 7, and 6 and washed with ethyl acetate after each adjustment. The aqueous solution was evaporated to dryness and the residue was triturated with methanolacetone to remove the amino acid from the inorganic salts. The organic solvents were removed in vacuo to give 0.25 g. of amino acid. The amino acid was compared on a thin layer chromatogram and in two diiferent solvent systems on paper chromatograms with authentic 3- morpholinomethyl 7 phenoxy-acetamido-A -cephem-4- carboxylic acid prepared in another way and was found to have a component with identical R in all cases. Two bioautographs against B. subtilis also verified the presence a of the desired A acid.

EXAMPLE 6 t-Butyl 3 bromomethyl 7 phenoxyacetamido-A cephem-4-carboxylate was prepared following the procedure of Examples 1-3. To a solution of this compound in 50 ml. of ethyl ether was added about 5 ml. of dimethylamine in 20 ml. of ether at ice temperature. The reaction mixture was stirred at 0 C. for three hours. The solvent was removed under reduced pressure and the residue was suspended in ethyl acetate. The ethyl acetate solution was washed twice with aqueous percent sodium bicarbonate solution, then extracted with 3 percent hydrochloric acid. The acidic solution was made basic with 5 percent sodium bicarbonate then extracted with ethyl acetate. The ethyl acetate solution was dried over anhydrous potassium carbonate and evaporated to dryness to give 2.3 g. of product. A nuclear magnetic resonance spectrum showed the product to be pure t-butyl 3 (-N,N-dimethylaminomethyl)-7-phenoxyacetamido-M-cephem-4-carboxylate.

EXAMPLE 7 The A ester from Example -6 was treated with triethylamine in an alcoholic solution as described in Example 5 to isomerize the double bond from the 2-position to the 3- position. Removal of the t-butyl ester group gave 3-(N,N- dimethylaminomet-hyl) 7 phenoxyacetamido-A3-cephem- 4-carboxylic acid.

EXAMPLE 8 To a solution of 5 millimoles of the 3-bromomethyl A ester from Example 3 in 100 ml. of ethyl ether at ice temperature was added a solution of 2 ml. of dimethylamine in 5 ml. of ether. The solution immediately became lighter in color and a yellow precipitate formed. After minutes at ice temperature the solution was washed with 5 percent sodium bicarbonate solution and the ether was extracted twice with 3 percent hydrochloric acid. The acid extract was adjusted to pH 8 with saturated sodium bicarbonate solution and extracted with benzene. The benzene solution was dried over sodium sulfate and evaporated to dryness to give 0.490 g. of product which was stirred with 5 ml. of pyridine in ml. of isopropanol at C. for 3 hours to complete isomerization. Removal of the solvent under reduced pressure gave 2-(2-methyl-3- butenyl) 3-(N,N-dimethylaminomethyl) 7 phenoxyacetamido-A -cephem-4-carboxylate.

EXAMPLE 9 A solution of 0.300 g. of the ester product from Example 8 in 5 ml. of 90 percent formic acid was stirred at 25 C. for 2 hours. The solution was then evaporated to dryness under reduced pressure. The crude product was examined by a bioautograph to confirm the presence of the expected 3-(N,N dimethylaminomethyl)-7-phenoxyacetamido-A -cephem-4-carboxylic acid.

EXAMPLE 1O 2-(2-methyl-3-butynyl) 3- (N,N-dimethylaminomethyl 7-phenoxyacetamido-A -cephem 4 carboxylate was prepared in a manner analogous to that described for the preparation of the corresponding t-butyl and 2-(2-methyl- 3-butenyl) esters. To an ice-cold solution of 104 mg. of the methylbutynyl ester in 15 ml. of a 2:1 isopropanolmethylene chloride solvent was added slowly a solution of 94.5 mg. of m-chloroperbenzoic acid in 8 ml. of a 1:1 isopropanol-methylene chloride solvent. After stirring one hour in the cold then one hour at room temperature the solvent was evaporated and the residue taken up in ethyl acetate. Extraction with cold 2.5 percent hydrochloric acid yielded a basic material after work-up. The basic material was dissolved in 2 ml. of 3:1 acetonitrile-dimethylformamide and the solution cooled. To this was added mg. of powdered stannous chloride and, after 20 minutes, 0.1 ml. of acetyl chloride. After stirring 50 minutes in the cold, the reaction mixture was evaporated to dryness, taken up in ethyl acetate and washed twice with sodium bicarbonate solution, once with sodium chloride solution, dried over magnesium sulfate, filtered and evaporated to give 26 mg. of material. This was dissolved in 15 ml. of methanol, 5 mg. of palladium on barium sulfate was added, and the mixture was hydrogenated for one hour. The methanol was evaporated, 3 ml. of 98-100 percent formic acid was added, and the mixture was allowed to stand for 20 minutes. The solution was evaporated to dryness, taken up in methanol, filtered, and evaporated to yield 18 mg. of crude 3-(N,N-dimethylaminomethyl)-7- phenoxyacetamido-A -cephem-4-carboxylic acid. This material gave a bioactive zone in bioautograms run in two different systems. The product was slightly slower moving than desacetoxy-cephalosporin V in wet methyl ethyl ketone and faster moving than cephaloglycin run in butanol-acetic acid-water.

We claim:

1. A compound having the formula where R is hydrogen, hydrogen and a C to C hydrocarbon sulfonic acid,

Q is hydrogen, hydroxy, chloro, bromo, C to C alkoxy,

nitro, or cyano;

Y is hydroxyl, amino and pharmaceutically acceptable salts thereof, or protected amino;

m is an integer of 0 to 2 n is an integer of 1 to 2;

X is oxygen or sulfur;

R is hydrogen or C to C alkyl and R is C to C alkyl or R and R taken together with the nitrogen to which they are bonded complete a pyrrolidino, piperidino, or morpholino ring;

R is hydrogen, a pharmaceutically acceptable cation, C to C t-alkyl, C to C t-alkenyl, C to C t-alkynyl, benzyl, methoxybenzyl, nitrobenzyl, benzhydryl phthalimidomethyl, succinimidomethyl, trimethylsilyl, or phenacyl.

2. A compound as in claim 1 wherein R is phenoxyacetyl, R and R are methyl, and R is hydrogen.

3. A compound as in claim 1 wherein R is phenoxyacetyl, R and R together with the nitrogen to which they are attached form a morpholino ring, and R is hydrogen.

References Cited UNITED STATES PATENTS 3,218,318 11/1965 Flynn 260243 C NICHOLAS S. RIZZO, Primary Examiner US. or. X.R. 424246 

